Odorless alkyl aryl sulfonate detergents



openness ALKYL ARYL SULFGNATE uETEnonNrs Richard D. ,Stayner, Berkeley,Calif., assignor to California Research? Corporation, San Francisco,Calif., a corporation of Delaware No Drawing. Application Mai-ch19, 1057Serial No. 646,957 t Claims. (Cl. 260-505) Thepresent invention relatesto a. process 'for producing' substantially odorless alkyl arylsulfonate'detergents and to alkyl aryl hydrocarbon compositions whichcan be converted to these substantially-odorless sulfonate detergents byknown processing'techniques of the art.

. detergents are polypropylene benzenes obtainable by alkylating benzenewith a propylene polymer fraction containing from 9' to 18 carbon atomsin the polymer chain,

and keryl benzenes produced by chlorinating kerosene and condensing theresulting alkyl chlorides with benzene.

It has been observed that upon completion of the sequence of sulfonationand neutralization steps in the manufacture of the aforementionedsulfonate' detergents,- particularly when branched-chain alkyl benzenesare employed for the sulfonation, the resulting neutralized sulfonateslurry has a rather unpleasant odor which resembles the characteristicodor of neutralized petroleum sludge produced in the sulfuric acidtreatment of petroleum fractions. blended with builders, in accordancewith therconven- When alkyl aryl sulfonate detergents are tionalprocedures of the art, to produce a final deter- 1 gent compositioncontaining from about 15 to about 40% of active detergent materials, theintensity of the odor is reduced; however, even after drying of theslurry to a solid particle-form material, the odor still remains highand persistent, and is diflicult to mask by the conventional addition ofperfume.

As a matter of fact, two types of odors have been observed in alkyl arylsulfonate detergents: (1) the aforebenzyl amino-phenol; and heterocyclicorganic compound, for instance, coumarin'or dextrose. In. contrast Withthese disclosures of the prior art which aimed at the elimination oratleast a reduction of the rancid odor occurring upon storage, thepresent invention is concerned with the elimination of the neutralizedacid sludge odor which characterizes a freshly prepared alkyl arylsulfonate detergent. It has now been found that a" sub-' stantiallyodorless alkyl aryl 'sulfonate detergent may be obtained by sulfonatinga branched-chain alkyl benzene in the presence of from 0.02'to 0.1% of aquinone which may be either para-benzoquinone, or ortho-benzoquinone,

or toluquinone (o-methyl-p-benzoquinone), or a mixture thereof, based onthe weight of the alkyl benzene hydrocarbon material. Para-benzoquinoneis particularly effec-{ tive as an inhibitor of the neutralized acidsludge odor. The invention willbe better understood from the followingexamples of the preparation of the detergent sulfonates without and withthe quinone odor inhibitor.

Example 1 1A polypropylene benzene hydrocarbon (200 g.) of the typedescribed in the U. S. Patent No. 2,477,382- (issued to Lewis) andboiling in the range from about 500 F. to about 625 F., is sulfonatedwith 20% oleum. The acid is added to the hydrocarbon with constantstirring over a period of about one hour, a total ofthree mols ofsulfuric acid being added for each mol of thehydrocarbon. After theaddition of the acid. is com-- pleted, the acid-hydrocarbon mixture isdigested at a' temperature of from about 85 to about 105 F. for abouttwo hours, during which time the sulfonation reaction is completed. Theresulting sulfonation product mixture is neutralized with sodiumhydroxide. The resulting slurry has a strong odor characteristic ofneutralized petroleum acid sludge. A portion of this slurry' isdrum-dried, but the dried particle-form likewise has a typical strongsludge odor.

Example 2 After repeating the sulfonation described in Example 1 andafter the digestion of the sulfonation mixture, water is added theretoin an amount which reduces the concen-- tration of the unreactedsulfuric acid to 80% by weight. Upon settling for two hours at 140 F. anupper layer of predominantly alkyl benzene sulfonic acid and a Y lowerlayer of predominantly aqueous sulfuric acid are mentioned odor,reminiscent of the neutralized acid sludge, which comes out from thedetergent material immediately upon completion of the sulfonation andneutralization steps; and (2) a rancid odor which develops upon storageof sulfonate detergent formulations. This latter odor is morecharacteristic of thedetergents' derived from keryl benzene than of thepolypropylene-derived detergents. When the keryl benzene sulfonatedetergent compositions are stored at fairly high tempera? ture, thismarked disagreeable rancid odor invariably is developed. In the case ofpolypropylene benzene sulfonate detergents, this rancid odor is seldomobserved and then only after prolonged storage at high temperature andin the presence of considerableamounts of moisture.

The prevention of the rancid odor in detergents during their storage isdiscussed in U. S. Patents .Nos. 2,397,133, 2,469,376-and 2,469,378, allissued to Flett, who proposed to alleviate the drawback of rancid'odorby introducing into the detergent composition: hydroxyaromaticcompounds, for instance, alpha-naphthol and thymol; amino-aromaticcompounds, for instance, paraformed. The layers are separated, and thesulfonic acid layer is. neutralized with sodium hydroxide. The resultingneutralized slurry again displays a strong odor characteristic of theneutralized acid sludge. When a portion of this slurry is drum-dried, itis observed that the sludge odor does not disappear.

Example 3 The process described in Example 1 is repeated. How

ever, before the acid is added to the alkyl benzene, a

small amount (0.1%) by weight of para-benzoquinone is dissolved in thealkyl benzene. The odor of the new tralized slurry is substantially lessintense than the odor from 0.02 to 0.1% by weight, based on the alkylbenzene,

Eatented Apr. 15, 1958 toluquinone, and mixtures of ortho-benzoquinone,para-' benzoquinone and toluquinone similarly efiect a reduction of theneutralized acid sludge odor in the sulfonated and neutralized finalslurry or in the dried particulate sulfonate product, provided thesequinone additions are employed in a total amount of at least 0.01% byweight, and preferably from 0.02 to 0.1% by weight, based on the alkylbenzene hydrocarbon.

Although in the illustrative examples hereinabove, sodium hydroxide hasbeen employed as the neutralizing agent for the sulfonation product,other metal hydroxides, such as ammonium hydroxide, potassium hydroxide,calcium hydroxide or magnesium hydroxide may be used for theneutralization without any adverse eifect on the improvement of odor inthe final product in accordance with the invention. 7

The reduction of the sludge odor due to the addition of the quinonesachieved in accordance with the invention in the case of sulfonatesderived from polypropylene benzene, is achieved in the case of freshalkyl aryl sulfonate detergents produced from keryl beuzenes.

It is to be noted that the action of para-benzoquinone, 1L.ortho-benzoquinone and toluquinone in reducing the odor level of freshlyprepared alkyl aryl benzene sulfonates is specific. Other quinones, suchasanthraquinone, duroquinone, naphthaquinone, and phenanthroquinone areinefiective. In fact, when Example 1 is repeated with eitheranthraquinone or duroquinone, the odor of the neutralized slurry ispractically undistinguishable from the characteristic strong unpleasantodor of neutralized acid sludge, as observed for the slurry of the alkylaryl benzene sulfonate in Example 1.

The manner in which paraand/ or ortho-benzoquinone accomplish theelimination or at least a substantial reduction of the undesirable odorin the finished sulfonate detergent product is not understood. It isbelieved that the quinone additive must inhibit, during the sulfonation,the formation of the side-reaction products which impart the undesirableodor to the finished detergent product.

Theuse of benzoquinones and toluquinone in the manner describedhereinabove is effective only to inhibit the development of theneutralized acid sludge odor in the freshly prepared detergent. Shouldthe neutral sulfonate detergent product be stored at high temperature inthe presence of an appreciable amount of moisture and for a prolongedperiod of time, a rancid odor quite different from the odor of thefreshly prepared detergent is apt to develop, although usually thiswould not occur in actual practice in the case of alkyl aryl sulfonatedetergents prepared from polypropylene benzene. However,

to prevent the occurrence of this rancid odor in detergent sulfonatesprepared from keryl benzene and left in storage, it is recommended that,after-the sulfonation of the alkyl benzene containing the quinoneinhibitor dispersed therein and after the neutralization of theresulting sulfonation product, a small amount of hydroquinone, usuallyin an amount from 0.001 to 0.005% by weight, based on the alkyl benzenesulfonate, be added to the neu' tralized product slurry before dryingit.

As pointed out hereinbefore, in order to effect the desired suppressionof the neutralized sludge odor from the freshly prepared sulfonatedetergent product the quinone should be added to the alkyl benzeneeither prior to the mixing of the hydrocarbon and the sulfuric acid, orvery shortly after the mixing began. If added at a; later time, forinstance, towards the end of the sulcellent raw materials from which onecan produce alkyl aryl sulfonate detergents of good odor. Such solutionscan be conveniently prepared by the manufacturer of the alkyl benzenesand shipped to the manufacturers of detergents, who may then directlysulfonate the solution, neutralize the resulting sulfonation product,add the necessary builders, and dry the built neutralized slurry.

, Iclaim: j

1.. In a process for producing an alkyl aryl sulfonate detergentbysulfonating an alkyl benzene hydrocarbon having from 9 to 18 carbonatoms in its alkyl chain with concentrated sulfuric acid, neutralizingthe sulfonation product and drying the neutralized product, theimprovement which comprises dispersing from 0.02 to 0.1%, based on theweight of the alkyl benzene, of at least one quinone selected from thegroup consisting of parabenzoquinone, ortho-benzoquinone and toluquinonein the alkyl benzene hydrocarbon'before the sulfonation reaction iscomplete.

' 2. A process for producing an alkyl aryl sulfonate detergent bysulfonating an alkyl benzene hydrocarbon having from 9 to 18 carbonatoms in its alkyl chain with concentrated sulfuric acid in the presenceof 0.02 to 0.1% of at least one quinone selected from the groupconsisting at para-benzoquinone, ortho-benzoquinone and tolu-quinone,based on the weight of the alkyl benzene, neutralizing thesulfonationproduct, and drying the neutralized product.

3. A composition suitable for sulfonation and neutralization to producea neutral sulfonation product free of neutralized acid sludge odor,comprising an alkyl benzene hydrocarbon having 9 to 18' carbon atoms inthe alkyl chain, in which is dispersed from 0.02 to 0.1% by weight of atleast one quinone from the group consisting of para-benzoquinone,ortho-benzoquinone and toluquinone.

4. A composition suitable for sulfonation and new tralization to producea neutral sulfonation product essentially free of neutralized acidsludge odor, comprising an alkyl benzene hydrocarbon having 9 to 18carbon atoms in the alkyl chain, in which is dispersed from 0.02 to 0.1%by weight of para-benzoquinone.

'5. A composition as defined in claim 4, wherein said alkyl benzenehydrocarbon is polypropylene benzene.

. No references cited.

1. IN A PROCESS FOR PRODUCING AN ALKYL ARYL SULFONATE DETERGENT BYSULFONATING AN ALKYL BENZENE HYDROCARBON HAVING FROM 9 TO 18 CARBONATOMS IN ITS ALKYL CHAIN WITH CONCENTRATED SULFURIC ACID, NEUTRALIZINGTHE SULFONATION PRODUCT AND DRYING THE NEUTRALIZED PRODUCT, THEIMPROVEMENT WHICH COMPRISES DISPERSING FROM 0.02 TO 0.1%, BASED ON THEWEIGHT OF THE ALKYL BENZENE, OF AT LEAST ONE AQUINONE SELECTED FROM THEGROUP CONSISTING OF PARABENZOQUINONE, ORTHO-BENZOQUINONE AND TOLUQUINONEIN THE ALKYL BENZENE HYDROCARBON BEFORE THE SULFONATION REACTION ISCOMPLETE.
 3. A COMPOSITION SUITABLE FOR SULFONATION AND NEUTRALIZATIONTO PRODUCE A NEUTRAL SULFONATION PRODUCT FREE OF NEUTRALIZED ACID SLUDGEODOR, COMPRISING AN ALKYL BENZENE HYDROGEN HAVING 9 TO 18 CARBON ATOMSIN THE ALKYL CHAIN, IN WHICH IS DISPERSED FROM 0.02 TO 0.1% BY WEIGHT OFAT LEAST ONE QUINONE FROM THE GROUP CONSISTING OF PARA-BENZOQUINONE,ORTHO-BENZOQUINONE AND TOLUQUINONE.